P6 - Molecules And Matter 1️⃣✅ Flashcards
What is a plateau?
A horizontal part of a graph.
What is the equation for density?
density = mass/volume
What are the units of density?
kg/m3 or g/cm3
How do you work out volume?
length x width x height
How are particles positioned in a solid?
Particles are closely packed together and vibrate in fixed positions.
How are particles positioned in a liquid?
Particles slightly spread out, start to vibrate more and can flow or be poured.
How are particles positioned in a gas?
Particles are very far apart, vibrate much faster and move around quickly.
An object will float if an objects density is……..
lower than the density of the liquid it’s in.
What is sublimation?
The change of state between a solid and a gas.
What is boiling?
The change of state between a liquid and a gas, it only occurs when the temperature has reached or surpassed the boiling point of that substance.
What is evapouration?
The change of state between a liquid and a gas, it occurs at any temperature.
What is freezing?
The change of state between a liquid and a solid.
What is melting?
The change of state between a solid and a liquid.
What is condensation?
The change of state between a gas and a liquid.
What is internal energy?
The total potential and kinetic energy stored by the particles of a substance.
What is the equation for specific latent heat?
Energy = mass x specific latent heat.
What are the units of specific latent heat?
J/kg
What is specific heat capacity?
The amount of energy required to raise the temperature of 1kg of a substance by 1°C
What is specific latent heat?
the energy required to change the state of 1kg of a substance with no change in temperature
What is specific latent heat of fusion?
the energy required to change state from a solid to a liquid (melt) of 1kg of a substance with no change in temperature
What is specific heat of vaporisation?
the energy required to change state from a liquid to a vapour of 1kg of a substance with no change in temperature
What is the equation for specific heat capacity?
Energy = mass x specific heat capacity (c) x temp change
What is absolute zero?
The lowest temperature anything can be.
What temperature is absolute zero?
-273°C
What is Pascals?
The unit of pressure.
What is a Kelvin?
Kelvins are the unit of temperature that stats at absolute zero.
How do you convert kelvins to °C?
You would add 273.
What is Brownian Motion?
The observation of particles moving around via other particles we can see hitting each other.
How would you find the density of a regular object?
You would find its volume (L x W x H), then you would measure it on a mass balance to work out it’s mass (in kg). Finally you would substitute your numbers into the equation for density (D = M/V).
What is another word for scales?
Mass balance.
How would you find the density of a irregular object?
You would first use a mass balance to weigh it to work out its mass. Next you would fill a displacement can full of water and record how much water was originally in the can, lower your irregular object down attached to string and, wait for all the water to stop coming out of the spout. After that you would take the new amount of water away from the original to find the difference - then you have the volume! Finally you would substitute your numbers into the equation for density (D = M/V).
What is the triangle for the equation for specific latent heat?
E
————-
M | L
What is the triangle for the equation for density?
M
————-
D | V
What are the 3 things that can affect pressure?
- Temperature
- Concentration
- Volume
What does heating up a gas do to the pressure?
By heating up the gas, the particles would gain more kinetic energy, therefore increasing the frequency of the collisions, which also would involve more force due to inc kinetic energy. As pressure is depended on force and collisions, we can be sure that pressure increases with temperature
What does changing the concentration of a gas do to the pressure?
By increasing the concentration of gas there would be more particles in a given space, leading to more frequent colisions adn therefore an increase in pressure so,
As concentration increases, pressure increases
What does changing the volume of a gas do to the pressure?
My decreasing the volume of a container with the gas, there would be more particles per unit of volume, therefore increasing the frequency of collisions, leading to a higher pressure so,
As volume decreases, pressure increases
How is pressure in gasses caused?
By gas particles colliding with the walls of a container
Pressure and volume are ________ proportional
Pressure and volume are inversly proportional, meaning as one goes up, the other comes down
When using the equation PV = Constant, how would you work out the pressure of an object once compressed when you have both the pressure and the volume of the object prior to its compression.
Because pressure & volume are inversly proportional, when you change one, the other does the opposite, keeping them constant. Therefore if you were to calculate the constant of the object before compression, it would be equal to the constant after the compression: therefore e.g. Initial V= 5, Initial P= 3 so constant (PxV = Constant) would = 5 x 3 = 15; so as the constant would be the same regardless as pressure and volume are inversly porportional and always stay constant, you can just do the constant (15) divided by the changed volume/ pressure e.g. 3 to work out what the pressure/volume must have changed to e.g. 15/ 3 = 5 so new pressure = 5 as 5 x 3 would also = 15 (the same constant)
